Pathologies of the gastrointestinal (GI) tract may exist for a variety of reasons. Some examples of pathologies include bleeding, lesions, angiodisplasia, Crohn's disease, polyps, celiac disorders, and others. The majority of pathologies result in changes of color and/or texture of the inner surface of the GI tract.
As one example, color changes may be due to bleeding. Blood may be present within the digestive tract for a variety of pathological reasons, including ulcers, cancer, or other disease conditions. It is often difficult to detect the presence of blood within the GI tract, since bleeding can occur in difficult to reach locations. In addition, it is difficult to “see” inside the tract, especially in sections which are hard to reach such as the small intestines.
Several approaches have been used to try to detect the presence of blood within the GI tract. One approach has been the detection of blood in the feces by visual and/or chemical means. The main drawback of this approach has been that the concentration of blood in the feces is lower than the concentration of blood at the bleeding site since additional materials are accumulated along the GI passage. Therefore, the sensitivity of this approach is low. In addition, the specific bleeding site along the GI tract cannot be determined.
A second, more invasive technique, has been the use of an endoscope or enteroscope. This approach enables direct visualization of parts of the GI tract. However, most portions of the small intestine are inaccessible by this method.
Other examples of pathologies which may be detected based on the red part of the spectrum include active bleeding, blood clots, polyps, lesions, ulcerations, angiodisplasia and telangectasia. Pathologies which may be characterized by blue/violet color include arterio-venous malformation (AVM) and submucosal bleeding. AVM may also appear in red. In addition, some types of ulcers are characterized by white color.